1. Field of the Invention
This invention generally relates to voice communication systems.
2. Related Art
Public switched telephone network and Internet telephony voice communication devices are in wide spread use. A public switched telephone network telephony voice communication device uses a desktop or cordless telephone to make calls to a remote terminal. Further, cell phones utilize cellular networks and public switched telephone network to make calls to distant remote terminals.
Internet voice communication utilizes computers and Internet connections to make calls to remote locations. Internet voice communication devices include a personal or laptop computer, a headset and microphone or stand alone Internet phones. Typically, Internet phones allow the users to make calls to a remote desktop, cordless or cell phone. Today Internet calls are cost effective when compared to a public switched telephone network telephone call, especially, in case of a long distance call.
Among combined public switched telephone network/Internet voice communication devices that are available today are desktop, cordless phones that independently support Internet telephony and public switched telephone networks. An example of such devices, a Du@lphone, is produced by RTX Telecom A/S of Denmark. These phones comprise a handset that wirelessly communicates with a base unit. The base unit attaches via an RJ11 connector to the public switched telephone network, and via a universal serial bus (USB) port to a personal computer (PC). Once connected, the handset can place or receive either a typical public switched telephone network call or an Internet based call through the USB port and via the personal computer's Internet interface. In such devices, Internet and public switched telephone network calls operate independently.
In Internet telephony, quality of the communication pathway is a concern, especially, when low transfer rate modems are used. When an Internet call becomes inaudible or noisy, the user has to disconnect, i.e., terminate the call, and try again at another time. Similarly, public switched telephone network telephone calls may not provide acceptable voice quality in certain situations such as when calling a remotely located terminal. When experiencing unacceptable voice quality, the user has to terminate the public switched telephone network telephone call and try again with hopes of establishing acceptable quality.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of ordinary skill in the art through comparison of such systems with the present invention.